In a turbomachine, such as a turbine engine, air is pressurized in a compressor section then mixed with fuel and burned in a combustion section to generate hot combustion gases. The hot combustion gases are expanded within a turbine section of the engine where energy is extracted to provide output power used to produce electricity.
Components within the combustion section and the turbine section directly exposed to the hot combustion gases, such as, for example, rotating and stationary airfoils, i.e., blades and vanes, and flow path defining components, e.g., shrouds, platforms, ring segments, liners, transition ducts, etc., may be provided with internal cooling circuits that channel a cooling fluid, such as compressor discharge air, through the component. These types of components may also include film cooling passages that extend through external walls thereof for discharging the cooling air to the outside of the component to form a thin layer of film cooling air, which protects the component from the hot combustion gases.
Over time the external walls of components that are exposed to the hot combustion gases may deteriorate, which may deform the film cooling passages formed therein, thus reducing or destroying the functionality of the film cooling passages. Further, the film cooling passages may become blocked or clogged with debris that is picked up and carried by the hot combustion gases. In such cases, it may become necessary to re-form the cooling passages in the walls of the components.